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Created July 14, 2021, last updated almost 3 years ago.
Collection: 144, Score: 665, Trend score: 0, Read count: 924, Articles count: 7, Created: 2021-07-14 02:42:11 UTC. Updated: 2022-01-20 07:51:45 UTC.Notes
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Collected Articles
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The Pfizer–BioNTech COVID-19 vaccine was 91% effective in preventing infection with SARS-CoV-2 in phase 3 trials.
pearl -
Randomized Controlled Trial Multicenter Study
Safety and Efficacy of the BNT162b2 mRNA Covid-19 Vaccine.
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and the resulting coronavirus disease 2019 (Covid-19) have afflicted tens of millions of people in a worldwide pandemic. Safe and effective vaccines are needed urgently. ⋯ A two-dose regimen of BNT162b2 conferred 95% protection against Covid-19 in persons 16 years of age or older. Safety over a median of 2 months was similar to that of other viral vaccines. (Funded by BioNTech and Pfizer; ClinicalTrials.gov number, NCT04368728.).
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Comparative Study
SARS-CoV-2 mRNA Vaccines Foster Potent Antigen-Specific Germinal Center Responses Associated with Neutralizing Antibody Generation.
The deployment of effective vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is critical to eradicate the coronavirus disease 2019 (COVID-19) pandemic. Many licensed vaccines confer protection by inducing long-lived plasma cells (LLPCs) and memory B cells (MBCs), cell types canonically generated during germinal center (GC) reactions. ⋯ Importantly, GC responses strongly correlated with neutralizing antibody production. mRNA vaccines more efficiently induced key regulators of the Tfh cell program and influenced the functional properties of Tfh cells. Overall, this study identifies SARS-CoV-2 mRNA vaccines as strong candidates for promoting robust GC-derived immune responses.
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Pregnant women are at increased risk of morbidity and mortality from COVID-19 but have been excluded from the phase 3 COVID-19 vaccine trials. Data on vaccine safety and immunogenicity in these populations are therefore limited. ⋯ In this exploratory analysis of a convenience sample, receipt of a COVID-19 mRNA vaccine was immunogenic in pregnant women, and vaccine-elicited antibodies were transported to infant cord blood and breast milk. Pregnant and nonpregnant women who were vaccinated developed cross-reactive antibody responses and T-cell responses against SARS-CoV-2 variants of concern.
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Here we report on the antibody and memory B cell responses of a cohort of 20 volunteers who received the Moderna (mRNA-1273) or Pfizer-BioNTech (BNT162b2) vaccine against SARS-CoV-21-4. Eight weeks after the second injection of vaccine, volunteers showed high levels of IgM and IgG anti-SARS-CoV-2 spike protein (S) and receptor-binding-domain (RBD) binding titre. Moreover, the plasma neutralizing activity and relative numbers of RBD-specific memory B cells of vaccinated volunteers were equivalent to those of individuals who had recovered from natural infection5,6. ⋯ However, neutralization by 14 of the 17 most-potent monoclonal antibodies that we tested was reduced or abolished by the K417N, E484K or N501Y mutation. Notably, these mutations were selected when we cultured recombinant vesicular stomatitis virus expressing SARS-CoV-2 S in the presence of the monoclonal antibodies elicited by the vaccines. Together, these results suggest that the monoclonal antibodies in clinical use should be tested against newly arising variants, and that mRNA vaccines may need to be updated periodically to avoid a potential loss of clinical efficacy.
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Observational Study
SARS-CoV-2 mRNA vaccines induce persistent human germinal centre responses.
This reassuring study published in Nature by researchers from Wash U Med investigated persisting COVID immunity following the Pfizer mRNA vaccination (BNT162b2). Turner et al. looked at the presence of not only circulating antibody-secreting B cells, but also germinal centre B cells found in the axillary lymph nodes of 14 study volunteers.
While the persistence of mRNA-vaccine induced immunity to SARS-CoV-2 has already been demonstrated to last at least 6 months, and likely 12 months, we just do not yet have the data to know if or when vaccine boosters will be required beyond that.
Turner's study is particularly exciting because they found spike-protein binding B cells in the germinal centre of draining lymph nodes in all 14 post-immunisation participants for the full 15 weeks of the study. The germinal centre response was so vigorous and persistent that the researchers believe this could represent COVID-protection lasting for years.
"Ellebedy said the immune response observed in his team’s study appears so robust and persistent that he thinks that it could last for years. The researcher based his assessment on the fact that germinal centre reactions that persist for several months or longer usually indicate an extremely vigorous immune response that culminates in the production of large numbers of long-lasting immune cells, called memory B cells. Some memory B cells can survive for years or even decades..." – Dr Francis Collins, NIH Directors Blog
This study builds on the same team's earlier work (Turner 2021 May) looking at bone marrow plasma cells in those who have recovered from mild COVID infection, also showing a long-lived immune response.
COVID persistent immunity takeaway:
Although COVID-19 and developed vaccines have been circulating for only 12-18 months, these immune-response studies give some hope that the miracle of mRNA vaccines may not only be in their efficacy, but also in the longevity of protection.
summary -
Bone marrow plasma cells producing antibodies to the SARS-CoV-2 spike protein likely provide robust and long-lived immunity after mild COVID-19.
pearl
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